The 23-year-old from Volgograd has taken women's pole vaulting to a new level since breaking the world record for the first time in Gateshead two years ago.

And breaking the 5m barrier at the Norwich Union London Grand Prix at Crystal Palace on Friday is certainly a landmark achievement.

But because women's pole vault is still evolving, not everyone believes it is necessarily the major breakthrough it seems.

"It's difficult to rank Isinbayeva's achievement with events such as the first four-minute mile and the first sub-10 second 100m," says BBC Sport commentator Steve Cram.

"Those events have been around longer so we just don't have the comparisons."

The event is so new that governing body the IAAF only began ratifying world records in 1995, when the first mark of 4.05m was set by China's Sun Caiyun.

By the time it was first included in the 2000 Olympics, Stacy Dragila had soared more than half a metre higher, taking the gold medal with 4.60m.

The American did much to widen the appeal of the sport, setting eight outdoor world records and becoming the first woman to go over 4.80m.

But it was not long before Dragila herself was left behind, first by Russian Svetlana Feofanova and then her arch-rival Isinbayeva.

Each athlete brought new skills to the event.

While Dragila trained as a heptathlete before switching events, Feofanova was a gymnast, possessing the kind of gravity-defying qualities that made her a natural for her new event.

Isinbayeva, in contrast, was a pole vaulter from the start, combining her obvious talent with the crucial ingredients of drive, determination and professionalism.

Three years after the IAAF officially recognised the sport, she took part in her first major competition - the 1998 World Junior Championships - aged just 16.

Then in 1999 she won her first gold medal at the World Youth Games with a clearance of 4.10m.

In 2004, she claimed her first major gold at the World Indoors with a world record-breaking mark of 4.86m.

And since that breakthrough, the 5m-mark has seemed inevitable, especially given her coach's regular reports that she often goes beyond that height in training.

In fading daylight but in perfectly still conditions, Isinbayeva finally emulated what she has done countless times in practice at the London Grand Prix.

The sell-out crowd at Crystal Palace saw for themselves her unique way of psyching herself up.

Prior to each vault, Isinbayeva indulges in a one-on-one chat with her pole, chanting a secret mantra over and over in a bid to generate extra power.

Just what she says to her pole remains a secret - but the ritual is clearly paying off.

Cynics have suggested Isinbayeva has inched her way to 5m in order to claim the $50,000 bonus awarded for each new record set.

But the Russian insists the frequent cash injections are not the chief motivating factor.

"Money is always nice and the more the better but it's not the reason why I compete and try to break records," she says.

"I chose to do it step by step. This way you have some suspense and it's more exciting for the audience."

Now the money is in the bank and the 5m-mark written into the record books, can we expect Isinbayeva to advance the sport further?

"Isinbayeva's feat will go down as a landmark achievement because she is setting the standards others can aim at," Cram told the BBC Sport website.

"She is so much better than everybody else so she will go higher. And we should see a knock-on effect in a couple of years with other athletes doing the same.

"Sergei Bubka has said for a while that 5m should be the true benchmark for world-class women's pole vault. Now Isinbayeva has made that a reality."